Ink jet recording head having spacer with etched pressurizing chambers and ink supply ports

ABSTRACT

A pressurizing chamber  1  is formed as a recess by half etching of a silicon single-crystal substrate  2 . A nozzle communicating hole  6  through which the pressurizing chamber  1  is connected to a nozzle opening  5  is formed as a through hole which is smaller in width than the pressurizing chamber  1 . The pressurizing chamber  1  is connected to the nozzle opening  5  in the other face via the nozzle communicating hole  6  while reducing the volume of the pressurizing chamber  1  to a degree as small as possible. The silicon single-crystal substrate is used as a member constituting a spacer so that an ink drop of a reduced ink amount suitable for high density printing flies with high positioning accuracy.

BACKGROUND OF THE INVENTION

[0001] The invention relates to an ink jet recording head in which asilicon single-crystal substrate is used for a spacer forming member,and a method of producing such an ink jet recording head.

[0002] An ink jet recording head has a pressurizing chamber formed byrespectively attaching a nozzle plate in which nozzle openings areformed and an elastic plate to both faces of a spacer with an adhesive.The elastic plate is deformed by a piezoelectric vibrating element.Since the ink jet recording head of this type. does not utilize athermal energy as a driving source for ejecting ink drops, the inkquality is not thermally changed. Particularly, therefore, it isavailable to eject color inks which may easily be thermallydeteriorated. In addition, an amount of displacement of thepiezoelectric vibrating element can be adjusted so that the ink amountof each ink drop is desirably regulated. For these reasons, such a headis most suitably used for configuring a printer for color printing witha high quality.

[0003] When color printing with a higher quality is to be performed byusing an ink jet recording head, higher resolution is required. As aresult, sizes of a piezoelectric vibrating element, a partition wall ofa spacer member, and the like are inevitably reduced so that higherprecision is required in the steps of working and assembling suchmembers.

[0004] Accordingly, it has been studied that members for an ink jetrecording head are worked by adopting a parts-manufacturing techniqueutilizing anisotropic etching of a silicon single-crystal substrate inwhich minute shapes can be worked with high accuracy by a relativelyeasy method, i.e., a so-called micro machining technique. Varioustechniques and methods are proposed, for example, in Japanese PatentApplication Laid-open Nos. Hei. 3-187755, Hei. 3-187756, Hei. 3-187757,Hei. 4-2790, Hei. 4-129745, and Hei. 5-62964.

[0005] When color images or characters are to be printed with a highquality, it is required not only to increase the arrangement density ofnozzle openings, but also to perform the printing by a so-called areagradation in which the area of one dot is varied in accordance with animage signal. In order to perform such an area gradation, the ink amountof each ink drop in one ejecting operation must be reduced to be assmall as possible, and high-speed driving must be enabled, therebyrealizing a recording head by which one pixel can be printed by severalejections of ink drops.

[0006] To comply with this, first, the displacement amount of thepiezoelectric vibrating element must be reduced, and the displacementmust be instantaneously reflected as a volume change of a pressurizingchamber. In addition, in order to link the small volume change of thepressurizing chamber to the ejection of ink drops, it is necessary toreduce the pressure loss in the pressurizing chamber to a level as smallas possible.

[0007] In order to efficiently link the displacement of thepiezoelectric vibrating element to the volume change of the pressurizingchamber, it is essential to increase the rigidity of the pressurizingchamber. In order to reduce the pressure loss in the pressurizingchamber, it is essential to make the volume of the pressurizing chamberas small as possible.

[0008] In order to reduce the volume of the pressurizing chamber, it isfirst considered that the opening area of a spacer which forms thepressurizing chamber is reduced. In view of the working accuracy of thepiezoelectric vibrating element which abuts against the spacer, thereduction is limited to about one arrangement pitch of the nozzleopenings at the maximum. For this reason, the reduction of the volumemust be realized by decreasing the depth of the pressurizing chamber.

[0009] In view of the handling of a spacer in the assembling step or thelike, however, the spacer must have the rigidity of some extent. Tocomply with this, a silicon single-crystal having a thickness of atleast 220 μm must be used as a silicon single-crystal substrate whichconstitutes the spacer. If a thin substrate having a thickness less than220 μm, the rigidity is very low. This produces a problem in thatdamages or unpredictable warpage may disadvantageously occur in theassembling step.

[0010] As a method of forming a shallow pressurizing chamber in asufficiently thick silicon single-crystal substrate by anisotropicetching, it may be contemplated to use a technique in which only oneface of the silicon single-crystal substrate is etched, i.e., aso-called half etching method. Since the pressurizing chamber must becommunicated with a nozzle opening for ejecting ink drops, it isnecessary to form a through hole which elongates from the face where anozzle plate is provided to the pressurizing chambers.

[0011] As well known in the art, in order to form a through hole H byanisotropic etching, as shown in FIG. 27, it is necessary to set anopening length so as to be about 1.7 (the square root of 3) or moretimes as large as the thickness of the silicon single-crystal substrate.If the employed substrate has a thickness of 220 μm or more, the minimumlength of the opening of the through hole is about 380 μm.

[0012] As thus constructed, the volume of a communicating hole causesthe volume of the pressurizing chamber to increase. In addition, thesize of the communicating hole is equal to the thickness of the siliconsingle-crystal substrate, i.e., 220 μm, and the length in thelongitudinal direction is 380 μm. Accordingly, there arises a problem inthat the opening area of the silicon single-crystal substrate isincreased and eventually the rigidity of the spacer is disadvantageouslydegraded.

[0013] In a recording head which uses a spacer made of a siliconsingle-crystal substrate, a piezoelectric vibrating element 130 of thelongitudinal vibration mode is used as an actuator as shown in FIG. 28.The piezoelectric vibrating element 130 of the longitudinal vibrationmode is fixed to a frame 135 together with a passage unit 134 whichcomprises an elastic plate 131, a spacer 132, and a nozzle plate 133, soas to be assembled in an ink jet recording head.

[0014] Distortion caused by a difference in coefficients of thermalexpansion between ceramic constituting the piezoelectric vibratingelement 130 and a material constituting the frame 135, in general,plastic occurs substantially in a proportional manner to the length L ofthe piezoelectric vibrating element 130. When heat is applied in anadhering step so as to obtain a high adhesive strength and then thecondition is returned to a normal use condition, a temperaturedifference of 40° C. or more occurs. In the case where the effectivelength L of the piezoelectric vibrating element 130 is 5.5 mm, forexample, an expansion difference of about 10 μm is caused by theabove-mentioned difference, so that the elastic plate 131 may bedamaged. Although such a damage may not be caused, the passage unithaving a relatively low rigidity is distorted by the stress caused bythe difference in thermal expansion. As a result, there arises a problemin that the flying directions of ink drops go out of alignment anderrors are caused in hitting positions, thereby degrading the printingquality.

SUMMARY OF THE INVENTION

[0015] The invention provides an ink jet recording head comprising: aspacer in which pressurizing chambers, an ink supply port, and a commonink chamber are formed by anisotropic etching of a siliconsingle-crystal substrate; a nozzle plate having nozzle openings at thesame pitches as those of the pressurizing chambers; and an elastic platewhich causes the pressurizing chambers to expand and contract, thenozzle plate being attached to one face of the spacer, the elasticplates being attached to the other face of the spacer. In the ink jetrecording head, the pressurizing chambers are formed as recesses by halfetching of the silicon single-crystal substrate, and nozzlecommunicating holes through which the pressurizing chambers areconnected to the nozzle openings are formed as through holes each havinga size smaller than a width of each of the pressurizing chambers, byfull etching of the silicon single-crystal substrate. The common inkchamber is formed as a through hole by full etching of the siliconsingle-crystal substrate. Since each of the pressurizing chambers isformed as a recess, the volume of the pressurizing chamber is reduced toa degree as small as possible. Each of the pressurizing chambers isconnected to the corresponding nozzle opening on the other face side viathe nozzle communicating hole, so that the effective volume related tothe ejection of ink drops is reduced. The ratio occupied by throughholes is reduced so that the inherent rigidity of the siliconsingle-crystal substrate is effectively used.

[0016] It is a first object of the invention to provide a novel ink jetrecording head in which a silicon single-crystal substrate having athickness as large as possible is used as a base material and whichcomprises a pressurizing chamber having a depth smaller than a thicknessof the silicon single-crystal substrate.

[0017] It is a second object of the invention to provide an ink jetrecording head in which degradation of the printing quality and damagesdue to a difference in thermal expansion between a piezoelectricvibrating element and a head unit or a frame are prevented fromoccurring.

[0018] It is another object of the invention to propose a method ofproducing the above-mentioned ink jet recording head.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019]FIG. 1 is a view showing one embodiment of an ink jet recordinghead of the invention in a section structure taken along the directionof arranging pressurizing chambers; FIG. 2 is a view showing apressurizing chamber of the ink jet recording head in a sectionstructure taken along the longitudinal direction; and FIG. 3 is a topview showing an embodiment of a spacer of the ink jet recording head.

[0020] FIGS. 4(I) to 4(IV) are views illustrating a method of producingthe spacer in the recording head.

[0021]FIGS. 5a and 5 b are views of another embodiment of the inventionin a top structure of a spacer and a section structure thereof,respectively; FIG. 6 is a view of another embodiment of the invention ina section structure of a spacer; FIGS. 7a and 7 b are views of anotherembodiment of the invention in a top structure of a spacer and a sectionstructure thereof, respectively; and FIG. 8 is a view showing a sectionstructure of the above-mentioned spacer taken along the direction ofarranging pressurizing chambers.

[0022]FIGS. 9a and 9 b are views of another embodiment of the inventionin a top structure of a spacer and a section structure thereof,respectively; and FIGS. 10a and 10 b are views of another embodiment ofthe invention in a top structure of a spacer and a section structurethereof, respectively.

[0023] FIGS. 11(I) to 11(IV) are views respectively illustrating othersteps of forming a through hole functioning as a nozzle communicatinghole by anisotropic etching.

[0024] FIGS. 12(I) and 12(II) are views respectively illustrating stepsof forming a through hole and a nozzle communicating hole by anisotropicetching.

[0025]FIGS. 13a and 13 b are views showing another embodiment of theinvention in which a common ink chamber is formed as a recess, in asection structure taken along a longitudinal direction of a pressurizingchamber of a spacer, respectively.

[0026]FIGS. 14a and 14 b are views showing another embodiment of theinvention in which a common ink chamber is formed as a recess, in asection structure taken along a longitudinal direction of a pressurizingchamber of a spacer, respectively.

[0027]FIG. 15a and FIG. 15b are views showing another embodiment of theinvention-in which a common ink chamber is formed as a recess, in asection structure taken along a longitudinal direction of a pressurizingchamber of a spacer, respectively.

[0028]FIG. 16 is a view showing an embodiment of the ink jet recordinghead of the invention in a section structure in the vicinity ofpressurizing chambers; and FIG. 17 is a top view showing a structure ofa spacer with removing an elastic plate of the recording head.

[0029] FIGS. 18(I) to 18(V) are views illustrating steps of the firsthalf of a method of producing the recording head, respectively; andFIGS. 19(I) to 19 (III) are views illustrating steps of the second halfof the method of producing the recording head, respectively.

[0030]FIG. 20 is a section view showing an embodiment of the ink jetrecording head of the invention; and FIGS. 21a and 21b are section viewsshowing an embodiment of a frame, in a structure of a sectionperpendicular to a side wall and that of a section parallel to the sidewall, respectively.

[0031]FIG. 22 is a view showing a structure in the vicinity of anopening of a frame; and FIG. 23 is a view showing an embodiment of apositioning structure using a frame of a piezoelectric vibrating elementunit.

[0032]FIG. 24 is a section view showing another embodiment of theinvention; and FIG. 25 is a section view showing a positioning structureof a piezoelectric vibrating element unit in the embodiment.

[0033]FIG. 26 is a section view showing another embodiment of theinvention.

[0034]FIG. 27 is a diagram showing a through hole formed by anisotropicetching of a silicon single-crystal substrate.

[0035]FIG. 28 is a diagram showing joint relationships among apiezoelectric vibrating element, a passage unit, and a frame in a priorart ink jet recording head.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0036] Hereinafter, embodiments of the invention shown in the figureswill be described in detail.

[0037]FIGS. 1 and 2 show an embodiment of the invention in a sectionstructure in the vicinity of pressurizing chambers 1. FIG. 3 shows a topstructure of a spacer 2 according to the present invention. The spacer 2is formed by subjecting anisotropic etching on a silicon single-crystalsubstrate used as a base material, having the surface of a predeterminedcrystal orientation, for example, a crystal orientation (110). On oneface, formed are the pressurizing chamber 1 having a depth D1 which issmaller than the thickness T1 of the silicon single-crystal substrateconstituting the spacer 2, and an ink supply port 3.

[0038] A common ink chamber 4 is formed as a through hole so as to becommunicated with the ink supply port 3. On one end of the pressurizingchamber 1, a nozzle communicating hole 6 is formed for connecting thepressurizing chamber 1 to a nozzle opening 5. In order to increaseflexibility in connection to the nozzle opening 5, a recess 8 is formedin the nozzle communicating hole 6 on the side of a nozzle plate 7. Therecess 8 is larger than the diameter φ of the inflow side of the nozzleopening 5. The recess 8 has a width W2 which is smaller than the widthW1 of the pressurizing chamber 1, and has a depth D2 which issubstantially equal to the depth D1 of the pressurizing chamber 1 andthe ink supply port 3.

[0039] The ink supply port 3 is formed as a recess having a depth whichis equal to the depth D1 of the pressurizing chamber 1, but narrowerthan the pressurizing chamber. Namely, the width W3 of the ink supplyport 3 is substantially one half of the width W1 of the pressurizingchamber 1. According to this configuration, ink which has beenpressurized in the pressurizing chamber 1 is suppressed so as not toreturn to the side of the common ink chamber 4 as much as possible,thereby allowing a much more amount of ink to be ejected through thenozzle opening 5.

[0040] The pressurizing chamber 1, the ink supply port 3, and the recess8 are formed by so-called half etching in which anisotropic etching isperformed from one face of a silicon single-crystal substratefunctioning as a base material of the spacer 2, and the etching isstopped when the etched depths of D1 and D2 are attained.

[0041] The common ink chamber 4 is required to have a large opening areafor covering all of the pressurizing chamber 1 arranged in one row.Thus, the common ink chamber 4 is formed as a through hole by performinganisotropic etching on both faces of the silicon single-crystalsubstrate.

[0042] On the other hand, the nozzle communicating hole 6 for connectingthe pressurizing chamber 1 to the nozzle opening 5 of the nozzle plate 7is formed so as to elongate in a longitudinal direction of thepressurizing chamber 1 by full etching so that a length L1 required forpassing through (L1 is the square root of 3 times or more as much as thethickness T1 of the silicon single-crystal substrate) is attained in thelongitudinal direction of the pressurizing chamber 1, while suppressingthe width W4 to be as small as possible.

[0043] Preferably, the thickness T2 of a partition wall of the nozzlecommunicating hole 6 is larger than the width W4 of the nozzlecommunicating hole 6. If the width W4 of the through hole constitutingthe nozzle communicating hole 6 is selected to be 70 μm or less, thethickness T2 of the partition wall of the nozzle communicating hole 6 isselected to be 70 μm or more, and the depth D1 of the pressurizingchamber 1 is selected to be 60 μm or less, for example, the complianceof the pressurizing chamber 1 can be made as small as possible. If thediameter of the nozzle opening 5 is about 25 μm, ink drops of about 10nanogram (about 10×10⁻⁶ mm³) can be ejected and they-can be caused tofly at a velocity of 7 meters per second or higher in the air.

[0044] In the thus configured spacer 2, an elastic plate 10 having adeformable thin portion 10 a and a thick portion 10 b for efficientlytransmitting the vibration of the piezoelectric vibrating element 11 tothe whole of the pressurizing chamber is fixed to the face on the sideof the pressurizing chamber, and the nozzle plate 7 is fixed to theother face. These elements are assembled into a passage unit 13. An endof the piezoelectric vibrating element 11 abuts against the thickportion 10 b via a head frame which will be described later, so as toconstitute a recording head.

[0045] In the embodiment, when a driving signal for expanding thepiezoelectric vibrating element 11 is applied, the elastic plate 10 isexpanded and displaced to tile side of the pressurizing chamber 1 so asto cause the pressurizing chamber 1 to contract. Accordingly, ink in thepressurizing chamber 1 is pressurized and ejected as an ink drop fromthe nozzle opening 5 via the nozzle communicating hole 6.

[0046] The pressurizing chamber 1 is configured so as to have the depthD1 which is smaller than the thickness T1 of the silicon single-crystalsubstrate constituting the spacer 2, and the nozzle communicating hole 6is formed so as to have the width W4 which is to be as small aspossible. As a result, the rigidity of the region forming thepressurizing chamber is increased. Accordingly, the expansion andcontraction of the piezoelectric vibrating element 11 which is displacedby a very minute distance and which is impulsively deformed are absorbedat a reduced ratio by a wall 2 a for partitioning the pressurizingchambers 1. Therefore, the expansion and contraction of thepiezoelectric vibrating element 11 efficiently act on the change of thevolume of the pressurizing chamber 1, and an ink drop of a small inkamount can be surely ejected at a predetermined velocity. As therigidity of the spacer 2 is increased, the deformation of the passageunit 13 caused by the displacement of the piezoelectric vibratingelement 11 is reduced. Consequently, the precision of arrival positionsof ink drops can be maintained. Since the effective volume of thepressurizing chamber 1 is small, the flow of the ink accommodatedtherein can sufficiently follow the piezoelectric vibrating element 11of a longitudinal vibration mode which can be driven at a high speed,with the result that the repetition frequency of ink drop ejection isincreased.

[0047] According to the above-described recording lead of the invention,the above-mentioned features cooperate so that, in response to aprinting signal for one pixel, minute ink drops can impact againstprinting paper at one point, at a constant velocity, and with highpositioning accuracy, thereby enabling pixels to be represented by areagradation.

[0048] Next, a method of producing the above-described passage unit 13will be described with reference to FIGS. 4(I) to 4(IV).

[0049] In FIG. 4(I), the reference numeral 20 designates a siliconsingle-crystal substrate having the surface of a crystal orientation(110) and having a thickness at which the substrate can be easilyhandled in an assembling step, for example, a thickness of 220 μm. Onboth faces thereof, etching protecting films 23 and 24 of silicondioxide (SiO₂) are formed. The etching protecting films 23 and 24 havewindows 21 and 22 in through hole regions, i.e., in regions where thenozzle communicating hole 6 is to be formed, in the figure.

[0050] In regions corresponding to a pressurizing chamber 1 and a recess8 for the connection to a nozzle opening 5, thick etching protectingfilms 25 and 26 of silicon dioxide (SiO₂) which can bear the formationof a through hole are formed.

[0051] Under this condition, the silicon single-crystal substrate 20 isimmersed in an anisotropic etching fluid of an aqueous solution ofpotassium hydroxide (KOH) of a concentration of about 25 wt % which iskept at 80° C. Then, the anisotropic etching is started from both facesor the windows 21 and 22, so as to form a through hole 25 which willserve as the common ink chamber 4 and the nozzle communicating holes 6(FIG. 4(II)).

[0052] Thereafter, the protecting films 23 and 24 of silicon dioxide areetched away so that etching protecting films 29 and 30 having windows 27and 28 remain in regions which will serve as the pressurizing chamber 1and the recesses 8 for the connection to the nozzle opening 5 (FIG.4(III)). Anisotropic etching is performed in the same way as describedabove by immersing the silicon single-crystal substrate 20 in ananisotropic etching fluid.

[0053] The etching is stopped when the anisotropic etching reachespredetermined depths D1 and D2, so that a shallow recess 31 which willserve as the pressurizing chamber 1 and the ink supply port 3 is formedon one face, and a recess 32 serving as the recess 8 which will furtherserve as a communicating portion with the nozzle opening 5 is formed onthe other face (FIG. 4(IV)).

[0054] As a result, the pressurizing chamber 1, the ink supply port 3,and the recess 8 for the connection Lo a nozzle opening are formed asshallow recesses. In addition, the through hole 25 is formed. Thethrough hole 25 passes through the silicon single-crystal substrate 20from the recess 31 which is formed on one face and will serve as thepressurizing chamber 1, to the recess 32 for the connection to thenozzle opening which is formed on the other face. The through hole 25has the width W4 which is smaller than the width W1 of the pressurizingchamber 1.

[0055] At last, the etching protecting films 29 and 30 of silicondioxide (SiO₂) which are no more necessary are removed away. Asrequired, a silicon dioxide film is formed again on an entire surface.Thereafter, the elastic plate 10 is fixed to one face, and the nozzleplate 7 is fixed to the other face with an adhesive, thereby completingthe passage unit 13.

[0056] In the embodiment, the silicon dioxide (SiO₂) films are formed soas to have two levels of thickness. Accordingly, it is required toperform only one time the mask alignment process, with the result thatrelative positions of the recesses 31 and 32 with respect to the throughhole 25 can be set with high accuracy.

[0057] In the embodiment, in order to increase flexibility in theconnection of the nozzle opening 5 to the communicating hole 6, therecess 8 for the connection is formed. However, the formation has nodirect relationship to the function of the ink ejection, and hence theformation may be performed as required.

[0058] In the above-described embodiment, the nozzle communicating hole6 is formed in a region which overlaps the pressurizing chamber 1.Alternatively, as shown in FIGS. 5a and 5 b, an end 6 a may bepositioned outside the pressurizing chamber 1. In the alternative, ifthe pressurizing chamber 1 is shortened in the longitudinal direction,the through hole can be formed without increasing the volume of thepressurizing chamber 1. In addition, if slopes 6 a and 6 b are formed soas to guide the ink to the nozzle opening side, removal of air bubblescan be promoted.

[0059] In the above-described embodiment, the recess 8 for theconnection to the nozzle opening 5 is formed in a limited area in thevicinity of the nozzle opening 5. Alternatively, as shown in FIG. 6, arecess 35 having a width substantially equal to the width W2 of thepressurizing chamber 1 or the width W4 of the recess 8 may be formed.One end 35 a of the recess 35 is communicated with the common inkchamber 4 in a similar manner as the pressurizing chamber 1 and the inksupply port 3. The other end 35 b of the recess extends to a regionopposing the nozzle opening 5. In the alternative, the flexibility ofconnection to the nozzle opening 5 is increased. In addition, the recess35 may be utilized as a second ink supply port so that the ink supply tothe pressurizing chamber 1 after the ink drop ejection is performed fromboth faces, i.e., the surface and the back face.

[0060]FIGS. 7a, 7 b, and 8 show another embodiment of a spacer used inthe ink jet recording head of the invention. In a spacer 40, apressurizing chamber 41 and an ink supply port 42 are formed as recesseson one face by conducting anisotropic etching of a siliconsingle-crystal substrate having the surface of a crystal orientation(110) in the same way as described above. A nozzle communicating hole 43nozzle communicating hole 43 is a through hole which has a substantiallyL-like shape and which comprises portions 43 a and 43 b. The portion 43a having a width W5 which is about one half of the width W1 of thepressurizing chamber 41 is formed along one partition wall 41 a of thepressurizing chamber 41 and extends from one end of the pressurizingchamber 41 on the side of the nozzle opening to a region where a nozzleopening 5 is positioned. The portion 43 b in a region opposing thenozzle opening 5 has a width almost equal to the width of thepressurizing chamber 41.

[0061] As described above, the nozzle communicating hole 43 correspondsto one partition wall of the pressurizing chamber 41, and the width ofthe nozzle communicating hole 43 is increased at an end of thepressurizing chamber 41 on the nozzle opening side. This enables thewidth of the pressurizing chamber 41 to be made as small as possible,and the through hole to be formed so as to have a short length. Inaddition, a slope 43 d in which the nozzle opening side is placed downis formed so that the ink smoothly flows. As a result, it is possible toprevent stagnation of air bubbles caused by stagnation of ink fromoccurring.

[0062] Also in the embodiment, in the same manner as the above-describedembodiment, as shown in FIG. 8, the thickness T3 of the wall between thenozzle communicating holes 43 is formed so as to be larger than thewidth W5 of the nozzle communicating hole 43. Preferably, the width W5of the through hole constituting the nozzle communicating hole 43 isselected so as to be 70 μm or less, the thickness T3 of the wall betweenthe nozzle communicating holes 43 is selected so as to be 70 μm or more,and the depth of the pressurizing chamber 41 formed by half etching isselected so as to be 60 μm or less. In this case, the compliance of thepressurizing chamber 41 can be made as small as possible. As a result,ink drops of about 10 nanogram (10×10⁻⁶ mm³) can be ejected and causedto fly at a velocity of 7 meters or more per second from the nozzleopening having a diameter of 25 μm.

[0063] In the embodiment, one of the walls of the nozzle communicatinghole 43 corresponds to the partition wall 41 a of the pressurizingchamber 41. Alternatively, as shown in FIGS. 9(a) and 9(b), both wallsof through holes 43 a are off-set from partition walls 41 a and 41 b ofthe pressurizing chamber 41 to have a predetermined distancetherebetween. Desirably, as shown in FIGS. 10(a) and 10(b), a wall 43 cof the nozzle opening side is tapered so that the avoidance of airbubbles is enhanced.

[0064]FIGS. 11 and 12 show other embodiments of a method of forming thenozzle communicating hole 43, respectively. In the figures, a hole inthe vicinity of the pressurizing chamber is shown by way of an example.In FIGS. 11(I) to 11(IV), a hatched region indicates an etchingprotecting film.

[0065] As for the etching protecting film specified and shown byhatching, in the pressurizing chamber, an etching protecting film 50 isformed in a region where a recess is to be formed by half etching. Anarrow protecting film 51 which has a tapered end 51 a is formed in asubstantially center portion of the nozzle communicating hole 43 whichis to be formed as a through hole. A protecting film 52 which narrowlyelongates so as to divide the through hole is formed in a region formedso as to surround the nozzle opening. These protecting films areprovided after positioned on both faces of the silicon single-crystalsubstrate (FIG. 11(I)).

[0066] The silicon single-crystal substrate on which such etchingprotecting films are formed is immersed in an anisotropic etching fluid,and anisotropic etching is started from both faces. Regions on which theprotecting films are not formed are etched away, and an end 51 a of theregion protected by the protecting film 51 is also etched away (FIG.11(II)). When the etching on both faces proceeds in this way to passthrough the substrate, the region protected by the protecting film 51 isalso etched away, and the end 51 a thereof reaches the position of theprotecting film 52 (FIG. 11(III)). The etching is further performed sothat the rear end side 51 b of the protecting film 51 is separated fromthe portion protected by the protecting film 52 (FIG. 11(IV)).

[0067] The etching protecting films 50, 52, and 51 b which are left onthe face to be a pressurizing chamber are removed away (FIG. 12(I)).Thereafter, anisotropic etching is performed again. The etching isstopped when the etching reaches a depth which is optimum as thepressurizing chamber. As a result, recesses which will serve as thepressurizing chamber and an ink supply port are formed, and portions 61and 62 which are left on the end side of the pressurizing chamber areremoved away (FIG. 12(II)).

[0068] Also in the above-described embodiment, a recess (a recessindicated by the reference numeral 35 in FIG. 6) is formed on the backface opposing the pressurizing chamber so as to elongate from a commonink chamber 4 to a nozzle opening 5, thereby allowing ink from thecommon ink chamber 4 to be supplied to the pressurizing chamber 1through both of the surface and back faces.

[0069] In the embodiment, the common ink chamber 4 is formed as athrough hole. Alternatively, in order to further reduce the ink amountof an ink drop and to increase the rigidity so as to realize high-speeddriving, it is desired that the common ink chamber 4 is formed not as athrough hole but as a recess so that a bottom portion having a constantthickness is left in the spacer 2, in the same manner asthe-pressurizing chamber.

[0070] Specifically, as shown in FIGS. 13a and 13 b, a first common inkchamber 71 is formed on a face opposing the elastic plate. The firstcommon ink chamber 71 is formed as a recess which is communicated withall ink supply ports 42 connected to the respective pressurizingchambers 41. On the face opposing the nozzle plate 7, formed is a secondcommon ink chamber 72. The second common ink chamber 72 is formed as arecess which cooperates with the first common ink chamber 71 so as toensure a volume for accommodating ink required for printing.

[0071] In order to communicate the first common ink chamber 71 with thesecond common ink chamber 72, a connection hole 73 configured by athrough hole is formed at an appropriate position in a region in whichthe first common ink chamber 71 faces the second common ink chamber 72.The provision of the connection hole 73 increases the flowability of theink in the first and second common ink chambers 71 and 72.

[0072] According to the embodiment, when ink is supplied from the inktank to either of the first common ink chamber 71 on the side of theelastic plate 10 and the second common ink chamber 72 on the side of thenozzle plate 7, the ink flows into the other one of the common inkchambers 72 and 71 via the connection hole 73. Thus, in accordance withthe total volume of the two common ink chambers 71 and 72, an amount ofink required for the printing can be supplied to the pressurizingchamber 41 through the ink supply port 42 only, or in a condition inwhich the recess 74 and the nozzle communicating hole acre used. Thearea occupied by through holes formed in the whole of the spacer 40 isreduced, so that the rigidity of the spacer 40 is increased. Therefore,the assembling process is easily performed, and additionally, thewarpage of the whole recording head caused by the displacement of thepiezoelectric vibrating element 11 during printing is reduced in degreeso that the accuracy of the hitting positions of ink drops on therecording medium is enhanced.

[0073] In the embodiment, the recess 72 which forms the second commonink chamber 72 elongates to the vicinity of the nozzle opening.Alternatively, as shown in FIGS. 14a and 14 b, an end 72 a of the recessmay be stopped at a position in which a volume for a common ink chamberis ensured, and a nozzle connection hole 76 may be formed.

[0074] In the spacer 40 shown in FIGS. 13a and 13 b, a through holewhich will serve as a nozzle communicating hole 75, and a through holewhich will serve as the connection hole 73 for connecting the fistcommon ink chamber 71 to the second common ink chamber 72 are firstformed by anisotropic etching on both faces of a silicon single-crystalsubstrate. Next, recesses which will serve as the pressurizing chamber41 the ink supply port 42, and the first common ink chamber 71 areformed by half etching on one face of the silicon single-crystalsubstrate. A recess which will serve as the second common ink chamber72, and a recess 76 for facilitating the connection of the nozzlecommunicating hole 75 to the nozzle opening 5 may be simultaneouslyformed by half etching on one process for the surface and the back face,or separately in different steps.

[0075] In the embodiment, the second common ink clamber 72 is providedon the side of the nozzle plate 7. In the case where a sufficient volumecan be ensured as a common ink chamber in a recess on one face, it isapparent that the common ink chamber 71 may be provided only on the faceon which the pressurizing chamber 41 is formed, as shown in FIGS. 15aand 15 b.

[0076] In the spacer 40 shown in FIGS. 15a and 15 b, a through holewhich will serve as the nozzle communicating hole 75 is first formed byanisotropic full etching of a silicon single-crystal substrate. Then,recesses which will serve as the pressurizing chamber 41 the ink supplyport 42, and the common ink chamber 71 are formed by anisotropic halfetching on one face of the silicon single-crystal substrate. The recess76 through which the nozzle communicating hole 75 is to be communicatedwith the nozzle opening 5 is thereafter formed in one process by halfetching on the surface and the back face or separately by processes forthe surface and the back face. According to the embodiment, only thenozzle communicating holes 75 which discretely exist constitute throughholes, and hence the rigidity which is in the vicinity of the inherentrigidity of the silicon single-crystal substrate constituting the spacer40 can be effectively used. Thus, the nozzle plate 7 can be madethinner, and the nozzle opening 5 can be made smaller.

[0077]FIGS. 16 and 17 show a section structure in the vicinity of apressurizing chamber and a top structure of a spacer of anotherembodiment of an ink jet recording head of the invention, respectively.In the figures, the reference numeral 81 designates a spacer accordingto the present invention. In the spacer 81, a pressurizing chamber 82and an ink supply port 83 having a depth D3 which is smaller than thethickness T4 of the silicon single-crystal substrate are formed on oneface of a silicon single-crystal substrate having the surface of apredetermined crystal orientation, for example, a crystal orientation(110). A common ink chamber 84 formed as a through hole is formed atanother end of the ink supply port 83 so as to be communicated with theink supply port. A nozzle communicating hole 86 which is a through holefor connecting the pressurizing chamber 82 to a nozzle opening 85 isformed at another end of the pressurizing chamber 82.

[0078] The pressurizing chamber 82 and the ink supply port 83 are formedas shallow recesses by performing anisotropic etching on only one faceof the silicon single-crystal substrate functioning as a base materialof the spacer 81. The common ink chamber 84 is formed as a through holeby anisotropic etching on both faces of the silicon single-crystalsubstrate because the opening area is large.

[0079] On the other hand, the nozzle communicating hole 86 is requiredto have a diameter as small as possible. Therefore, the nozzlecommunicating hole is opened by irradiation of laser light from a laserapparatus using copper ions. A laser using copper ions has highabsorptivity with a silicon single-crystal substrate and is a pulselaser. Consequently, a hole can be gradually bored in such a manner thatvery thin layers are peeled one by one. As compared with the case wherecontinuous laser light from a carbon dioxide laser apparatus is used forboring a hole, the nozzle communicating hole 6 can be formed into acylindrical shape which has a circular section. As compared with thecase where a through hole is formed by anisotropic etching, ink can besmoothly supplied to the nozzle opening 5.

[0080] The thus configured spacer 81 is sandwiched by an elastic plate87 on the pressurizing chamber side and a nozzle plate 88 on the otherside, and they are integrally fixed to the spacer.

[0081] The elastic plate 87 comprises a vibration region which isconfigured as a thin portion 87 a, and a thick portion 87 b forefficiently transmit the vibration of a piezoelectric vibrating element89 to the whole of the pressurizing chamber. An end of thepiezoelectric-vibrating element 89 of the longitudinal vibration mode isfixed to the thick portion 87 b. In FIG. 16, the reference numeral 90designates a protecting film of a silicon dioxide film on a siliconsingle-crystal substrate which constitutes a spacer 81.

[0082] In the embodiment, a through hole for connecting the nozzleopening 85 to the pressurizing chamber 82 can be formed without beingaffected by the rule of anisotropic etching of a silicon single-crystalsubstrate, and hence it is possible to determine the thickness inconsideration of the rigidity which is to be provided in the spacer.Next, a method of producing the recording head will be described.

[0083] In FIGS. 18(I) to 18(V), the reference numeral 91 designates asilicon single-crystal substrate having the surface of a crystalorientation (110) and having a thickness at which the substrate can beeasily handled in an assembling step, for example, a thickness of 220μm. On at least one entire face of the substrate which is to besubjected to anisotropic etching, a silicon dioxide (SiO₂) film 92 isformed so as to have a thickness by which the film is allowed tofunction as a protecting film in an etching process described later, forexample, a thickness of 1 μm, by thermal oxidation in which heating isperformed at 1,000° C. for about four hours under an oxide atmospherecontaining water vapor (FIG. 18(I)).

[0084] A pattern corresponding to an opening shape of the common inkchamber is formed at a position where a common ink chamber 84 is to beformed, and then subjected to exposure and development so as to providea resist layer. An etching process using a silicon oxide etching fluid,for example, hydrofluoric acid buffer solution is performed so as toremove away a region of the silicon dioxide film 92 other than theresist layer, thereby forming windows 93 and 94 which will serve as thecommon ink chamber 84 (FIG. 18(II)).

[0085] Next, the substrate 91 is immersed in an aqueous solution ofpotassium hydroxide (KOH) of a concentration of 25 wt % which is kept at80°C. so that anisotropic etching is started from both faces or thewindows 93 and 94 in which the silicon dioxide film 92 is removed away.When a hole is bored by the etching through the substrate 91 in thisway, the formation of a through hole 95 which will serve as the commonink chamber 84 is completed (FIG. 18(III)).

[0086] Next, a window 96 is formed by removing the silicon dioxide film92 on one face in a region where the pressurizing chamber 82 and the inksupply port 83 are to be formed, in the same way as described above(FIG. 18(IV)). Thereafter, anisotropic etching is performed by using thesilicon oxide etching solution which is the same as described above. Inthis step, since the etching progresses from only one face, the etchingis stopped when the etching reaches a depth which is optimum as thepressurizing chamber 82, whereby a recess 97 is formed (FIG. 18(V)).

[0087] A position 97 a where the nozzle communicating hole 86 is to beformed in the recess 97 which will serve as the pressurizing chamber 82in which the nozzle communicating hole 86 is irradiated with a laserlight 98 from a copper-ion laser apparatus (FIG. 19(I)). Since the laserlight from the laser apparatus using copper ions is pulsatively excited,the silicon single-crystal substrate 91 and the silicon dioxide film 92which are irradiated are intermittently evaporated and removed away,with the result that a through hole 99 having a small diameter requiredfor the nozzle communicating hole 86 is bored (FIG. 10(II)).

[0088] In a stage in which the spacer is completed, the aforementionedelastic plate 87 is bonded to an opening face of the recess 97, and thenozzle plate 8 is bonded to the other face in such a manner that thenozzle opening 5 is communicated with the nozzle communicating hole 18,thereby completing a passage unit 13 which is the same as describedabove (FIG. 10(III)). In the thus configured passage unit 13, the spaceris made by the silicon single-crystal substrate 91 of a thickness of 220μm or more which can exhibit a strength sufficient for easy handling.Accordingly, warpage and bending of the elastic plate 8 and the nozzleplate 88 which may easily occur in an adhesion step for producing a headwith high printing density can be prevented from occurring as much aspossible.

[0089] In order to enhance affinity to the ink in the passage anddurability, the existing silicon dioxide film 92 may be removed away,and a silicon dioxide film may be formed again on the front face by athermal oxidation method. In the embodiment, the nozzle communicatinghole is formed by the radiation of laser light after the etching step.Alternatively, a nozzle communicating hole forming position of thesilicon single-crystal substrate is first irradiated with laser light,so that a through hole 99 which will serve as the nozzle communicatinghole 86 is bored. Thereafter, in the steps shown in FIGS. 18(I) to18(V), a through hole which will serve as the common ink chamber 4, andrecesses which will serve as the pressurizing chamber 2 and the inksupply port 3 may be formed. In addition, in the above-describedembodiment, the face on the side of the recess 97 which will serve asthe pressurizing chamber is irradiated with the laser light so as toform the through hole 99. Alternatively, the face on which the nozzleplate is provided may be irradiated with laser light, whereby thethrough hole 99 is bored.

[0090] Next, a technique for constructing a recording head by abuttingthe piezoelectric vibrating element 11 against the above-mentionedpassage unit 13 will be described.

[0091]FIG. 20 is a view showing a section structure of a recording headwhich is configured by using a frame 100 suitable for fixing the passageunit 13 and the piezoelectric vibrating element 11. FIGS. 21a and 21 bshow an embodiment of the frame 100.

[0092] The frame 100 is formed as a cylinder having an accommodatingchamber 101 for the piezoelectric vibrating element by injection moldingof a polymer material or the like. An opening 102 into which thepiezoelectric vibrating elements 11 are to be inserted is formed on oneend of the frame 100, and a fixing portion 103 to which the passage unit13 is to be fixed via an adhesive layer is formed on the other end. Onthe same face as the fixing portion 103, a window 104 for exposing anend 11a of the piezoelectric vibrating element 11 is formed. Inaddition, an overhang portion 105 which overhangs on the side of thewindow 104 and protrudes in the vicinity of the thick portion 87 b ofthe elastic plate 87 is formed.

[0093] The reference numeral 106 designates grooves for injecting anadhesive. A tapered portion 106 a for guiding the insertion of aninjection needle is formed at an upper end of each groove 106. Thegrooves 106 are formed so as to be symmetrical in the arrangementdirection. Each of the grooves 106 downwardly elongates from the taperedportion 106 a to the middle of the overhang portion 105 along a wallface 108 of the accommodating chamber 101 which opposes a fixingsubstrate 107 of a piezoelectric vibrating element unit 110. The grooves106 have a depth of, for example, about 0.2 mm by which the adhesive canflow into a region where the overhang portion 105 opposes an end 107 aof the fixing substrate 107 by a capillary force. The wall face 108 ofthe frame 100 is formed as a slope so as to form a wedge-like gap 109.As a result, the distance between wall face at the opening 102 and thefixing substrate 107 becomes larger.

[0094] As shown in FIG. 23, dummy vibrating elements 11′ and 11′ aredisposed in the vibrating element unit 110. The dummy vibrating elements11′ and 11′ are made of the same material as that of the piezoelectricvibrating elements 11 but are formed so as to be slightly thicker thanthe piezoelectric vibrating elements 11. The driving signal is notsupplied to the dummy vibrating elements 11′ and 11′. These vibratingelements are fixed to a rear end plate 111 at regular pitches, and therear end plate 111 is then fixed to the fixing substrate 107. In thefixing substrate 107, a slope 107 b is formed in the thickness directionso that an end of the fixing substrate 107 does not protrude from theoverhang portion 105 to the piezoelectric vibrating element 11 side.

[0095] Accordingly, the dummy vibrating elements 11′ and 11′ on bothside ends are in contact with a side portion 100 a of the opening 101 ofthe frame 100 when the vibration unit 110 is inserted into the frame100, so as to function as guiding members. As a result, thepiezoelectric vibrating elements 11 can precisely abut against the thickportion 87 b of the elastic plate 87.

[0096] The fixing substrate 107 is desirably made of a material having acoefficient of thermal expansion which is substantially equal to that ofthe piezoelectric vibrating element 11, for example, a piezoelectricmaterial or another ceramic material. In the case where the rigiditymust be ensured in order to prevent crosstalk caused by stress ofexpansion and contraction of the piezoelectric vibrating element 8 fromoccurring, the fixing substrate 107 may be made of a metal material. InFIG. 21a, the reference numeral 112 designates a wall for dividing theaccommodating chamber 101 of the frame into two chambers.

[0097] When a recording head is to be produced by using the thusconstructed frame 100, the frame 100 is set so that the fixing portion103 is placed upward, and the passage unit 13 is fixed to the fixingportion 103 via an adhesive layer. Then, the frame 100 is set again sothat the opening 101 is placed upward, and an adhesive is applied to theend 11 a of the vibrating element 11. When the vibrating element unit110 is inserted from the opening 101, both sides of the fixing substrate107 are guided by the guides 108 a on both sides of the wall face 108(FIG. 22), and the dummy vibrating elements 11′ and 11′ are downwardlyguided by a side portion 100 a of the frame. When the end 11 a of thepiezoelectric vibrating element 11 abuts against the thick portion 87 bof the elastic plate 87, the position of the piezoelectric vibratingelement 11 along the axial direction is determined.

[0098] At the stage where the positioning is compjeted, a gap existsbetween the fixing substrate 107 and the side wall 108, and a slight gapΔg is caused between the end 107 a of the fixing substrate 107 and thesurface of the overhang portion 105. Under this condition, when apredetermined quantity of liquid adhesive is injected by using aninjection needle or the like from the tapered portion 106 a of thegroove 106 formed on the side wall 108, the adhesive enters the spaceformed by the fixing substrate 107 and the groove 106, and thenpenetrates into the narrow gap Δg of the overhang portion 105 by acapillary force. The adhesive penetrating in the gap Δg is stopped bysurface tension at an end of the gap Δg between the overhang portion 105and the fixing substrate 107 by forming a meniscus. Thus, the adhesivewill not flow to the elastic plate 87. The adhesive in the groove 106penetrates also into a gap between the fixing substrate 107 and the sidewall 108 of the frame 100 by a capillary force, so that the adhesiveenters between the entire face of the fixing substrate 107 and the sidewall.

[0099] Under this condition, heating is performed up to a temperature atwhich the curing of the adhesive is promoted, for example, 60° C. Duringthe curing process, the frame 100 and the fixing substrate 107 areexpanded based on the coefficients of thermal expansion of theirrespective materials. The coefficients of thermal expansion of thepiezoelectric vibrating element 11 and the fixing substrate 107 areselected so as to be substantially equal to each other and the thicknessL₀ of the overhang portion 105 is about 1 mm. Even if the effectivelength L of the piezoelectric vibrating element 11 is as large as about5.5 mm, therefore, the difference in thermal expansion per temperaturedifference of 40° C. can be suppressed to be as small as 1 to 2 μm. Inthe conventional ink jet recording head (FIG. 28), the end portion ofthe piezoelectric vibrating element is fixed to the frame, and hence adifference in thermal expansion which corresponds to the effectivelength L =5.5 mm of the piezoelectric vibrating element is caused. Themagnitude of the difference is about 5 to 10 μm which is five (5) timesas large as that in the invention.

[0100] In the embodiment, the configuration foreliminating-disadvantages caused by the difference in the coefficientsof thermal expansion due to the difference in materials between thepiezoelectric vibrating element 11 and the frame 100 has been described.A large difference exists in the coefficients of thermal expansionbetween the silicon single-crystal substrate constituting the spacer 81which is the main component of the passage unit 13 and a polymermaterial constituting the frame 100. If the passage unit 13 is firmlyfixed to the frame 100 with an adhesive, therefore, there occurs aproblem in that a stress is caused by the difference in the coefficientsof thermal expansion in the plane direction of the passage unit 13, sothat warpage of the passage unit 13 degrades the printing quality.

[0101]FIG. 24 shows a further embodiment of the invention which solvessuch a problem. In the embodiment, a buffering member 116 having awindow 115 is interposed between a fixing portion 103 of a frame 100 anda passage unit 13, and the fixing portion 103 of the frame 100 is fixedto the passage unit 13 via the buffering member 116 with an adhesive.The buffering member 116 comprises an overhang portion 116 a formed insuch a manner that it does not interfere with displacement of an elasticplate 87 in at least a region opposing a pressurizing chamber. Theoverhang portion 116 a slightly protrudes from the frame 100 to the sideof the piezoelectric vibrating element 11 so as to form an adhesive facefor an end 107 a of a fixing substrate 107 of a piezoelectric vibratingelement unit 110. The end 107 a of the fixing substrate 107 is fixed byan adhesive P. In the arrangement direction of the piezoelectricvibrating elements 11, as shown in FIG. 25, dummy vibrating elements 11′and 11′ are guided, and the dummy vibrating elements 11′ and 11′function also as positioning members.

[0102] As a material for the buffering member 116, used is a materialhaving high rigidity for reinforcing the strength of the passage unit 13in the plane direction, having a linear expansion coefficient in themiddle of the linear expansion coefficient of the frame 100 and that ofthe silicon single-crystal substrate constituting the spacer 81, anddesirably having an ink resistant property. For example, stainlesssteel, specifically SUS430 having a linear expansion coefficient of9E-6/° C. is used, and is formed into the buffering member by metalpress working. As another example, a thermosetting resin may be used.The thermosetting resin can be easily worked into desired shape byinjection molding. In addition, it is possible to relatively easilyselect a material having high rigidity and having a linear expansioncoefficient in the middle of the linear expansion coefficients of thesilicon single-crystal substrate constituting the spacer 81 and theframe 100.

[0103] As described above, the buffering member 116 is interposedbetween the passage unit 13 and the frame 100, so that the strength ofthe passage unit 13 is reinforced by the rigidity of the bufferingmember 116. Furthermore, a difference in thermal expansion between thepassage unit 13 and the frame 100 is reduced, so that bend and warpageof the passage unit 13 caused by a temperature variation can beprevented from occurring as much as possible, and variations in ink dropejection performance can be suppressed.

[0104] In addition to the above-described construction, in the regionopposing the common ink chamber 84, a recess 117 may be formed on thecommon ink chamber side, and tile region of the elastic plate 87 may beformed as a thin portion 87 c, so that the compliance of the common inkchamber 87 is ensured. Thus, crosstalk can be more surely reduced. Forreference purposes, materials, linear expansion coefficients, Young'smodulus, plate thicknesses of elements constituting the recording headof the embodiment are listed in Table 1. TABLE 1 Liner expansion Young'sPlate coefficients modulus thickness Materials (E-6/° C.) (kg/mm²) (mm)Nozzle plate SUS316 17 19700 0.08 Spacer Si  2 15900 0.28 Vibrator PPS +SUS304 about 17 about 700 0.03 Frame Liquid 38  880 2 crystal polymerBuffer SUS430  9 20400 0.7 member

[0105] In the embodiment shown in FIG. 20, the groove 106 for injectingan adhesive extends to the overhang portion 105. Alternatively, as shownin FIG. 26, a groove 119 which is stopped at the overhang portion 105may be formed. In the alternative, the adhesive first enters the groove119 and then penetrates into a narrow wedge-like space 109 in which theupper portion is tapered and which is formed between the fixingsubstrate 107 and the side wall 108, and a gap between the end 107 a ofthe fixing substrate 107 and the overhang portion 105 by a capillaryforce, so as to spread therebetween. Accordingly, as compared with theembodiment shown in FIG. 20 in which the groove is formed tip to theoverhang portion 105, the disadvantage in that the adhesive isconcentrated in the vicinity of the groove 106 (FIG. 20) can beeliminated as far as the flatness of the fixing substrate 107 and theoverhang portion 105 is ensured. Thus, the adhesive can be surelydiffused to the entire overhang portion 105. In FIG. 26, the referencenumeral 119 a designates an adhesive injection port formed at the upperend of the groove 119.

What is claimed is:
 1. An ink jet recording head comprising: a spacerincluding, pressurizing chambers formed by anisotropic etching of asilicon single-crystal substrate, an ink supply port formed byanisotropic etching of a silicon single-crystal substrate, and a commonink chamber, communicating with the ink supply port; a nozzle platehaving nozzle openings at the same pitches as those of said pressurizingchambers; and an elastic plate which causes said pressurizing chambersto expand and contract, said nozzle plate being attached to one face ofsaid spacer, said elastic plate being attached to another face of saidspacer, wherein each of said pressurizing chambers has a recess by halfetching of said silicon single-crystal substrate, and a nozzlecommunicating hole through which said pressurizing chamber is connectedto respective one of said nozzle openings is formed as a through holehaving a size smaller than a width of said pressurizing chamber.
 2. Anink jet recording head according to claim 1, wherein the nozzle openingside of said silicon single-crystal substrate has a recess communicatingsaid nozzle communicating hole with said common ink chamber.
 3. An inkjet recording head according to claim 1, wherein a recess which islarger in area than said nozzle opening is formed in a region of saidsilicon single-crystal substrate opposing said nozzle opening.
 4. An inkjet recording head according to claim 1, 2, or 3, wherein a recess isformed in a region of said silicon single-crystal substrate opposingsaid nozzle opening, said recess being larger in width than said nozzleopening and said nozzle communicating hole, smaller in width than saidpressurizing chamber, and substantially equal in depth to said recess ofsaid pressurizing chamber.
 5. An ink jet recording head according toclaim 2, 3, or 4, wherein said recess opposing said nozzle openingelongates and is communicated with said common ink chamber.
 6. An inkjet recording head according to claim 1, 2, 3, or 4, wherein a recessconstituting said common ink chamber is formed at a depth which issubstantially equal to a depth of said recess of said pressurizingchamber.
 7. An ink jet recording head according to claim 1, wherein onewall in a longitudinal direction of said nozzle communicating holecoincides with a wall defining said pressurizing chamber, and saidnozzle communicating hole is formed as a through hole which isexpandingly opened in a region opposing said nozzle opening and on theside of said pressurizing chamber.
 8. An ink jet recording headaccording to claim 1, wherein both walls in a longitudinal direction ofsaid nozzle communicating hole are separated from a wall defining saidpressurizing chamber by a constant distance, and tapered in a regionopposing said nozzle opening so as for said nozzle communicating hole asa through hole.
 9. An ink jet recording head according to claim 1,wherein a thickness of walls separating said communicating holes fromeach other is larger than a width of said communicating holes.
 10. Anink jet recording head according to claim 1, wherein a portion of saidnozzle communicating hole in the vicinity of said nozzle opening isinclined toward said nozzle opening.
 11. An ink jet recording headaccording to claim 1, wherein a width of said nozzle communicating holeis 70 μm or less, and a depth of said recess formed by the half etchingis 60 μm or less.
 12. An ink jet recording head according to claim 1,wherein a width of said nozzle communicating hole is 70 μm or less, adepth of said recess formed by the half etching is 60 μm or less, and athickness of walls separating said communicating holes from each otheris 70 μm or more.
 13. A method of producing an ink jet recording head,comprising the steps of: (a) forming a nozzle communicating hole throughwhich a pressurizing chamber is communicated with a nozzle opening, byanisotropic etching performed on both faces of a silicon single-crystalsubstrate; (b) after said through hole is formed, forming a recess whichwill serve as the pressurizing chamber, by half etching performed on oneof the faces of said silicon single-crystal substrate; and (c) fixing anelastic plate to a face of said silicon single-crystal substrate inwhich said through hole and said recess are formed in the previoussteps, said face being on the side of said recess which will serve assaid pressurizing chamber, and fixing a nozzle plate to another face.14. A method of producing an ink jet recording head, comprising thesteps of: (a) forming a nozzle communicating hole through which apressurizing chamber is communicated with a nozzle opening, byanisotropic etching performed on both faces of a silicon single-crystalsubstrate; (b) after said through hole is formed, forming a recess whichwill serve as the pressurizing chamber, by half etching performed on oneof the faces of said silicon single-crystal substrate; (c) forming arecess for connection on a face opposing said nozzle opening, by halfetching; and (d) fixing an elastic plate to a face of said siliconsingle-crystal substrate in which said through hole and said recess areformed in the previous steps, said face being on the side of said recesswhich will serve as said pressurizing chamber, and fixing a nozzle plateto another face.
 15. A method of producing an ink jet recording head,comprising the steps of: (a) forming a nozzle communicating hole throughwhich a pressurizing chamber is communicated with a nozzle opening, byanisotropic etching performed on both faces of a silicon single-crystalsubstrate; (b) after said through hole is formed, forming a recess whichwill serve as the pressurizing chamber, by half etching performed on oneof the faces of said silicon single-crystal substrate; (c) forming arecess through which said nozzle communicating hole is communicated witha common ink chamber, on a face opposing said nozzle opening, by halfetching; and (d) fixing an elastic plate to a face of said siliconsingle-crystal substrate in which said through hole and said recess areformed in the previous steps, said face being on the side of said recesswhich will serve as said pressurizing chamber, and fixing a nozzle plateto another face.
 16. A method of producing an ink jet recording head,comprising the steps of: (a) forming a through hole which serves as anozzle communicating hole through which a pressurizing chamber iscommunicated with a nozzle opening, and forming a through hole whichserves as a connection hole in a region which serves as a common inkchamber, by anisotropic etching performed on both faces of a siliconsingle-crystal substrate; (b) after said through holes are formed,forming a recess which serves as the pressurizing chamber and a firstcommon ink chamber, by half etching performed on one of the faces ofsaid silicon single-crystal substrate; (c) forming a recess which servesas a second common ink chamber, by half etching performed on anotherface of said silicon single-crystal substrate; and (d) fixing an elasticplate to a face of said silicon single-crystal substrate in which saidthrough hole and said recess are formed in the previous steps, said facebeing on the side of said recess which serves as a first pressurizingchamber, and fixing a nozzle plate to another face.
 17. A method ofproducing an ink jet recording head according to claim 14, 15, or 16,wherein the half etching processes in said steps (b) and (c) aresimultaneously performed on both faces of said silicon single-crystalsubstrate.
 18. An ink jet recording head comprising: a spacer havingpressurizing chambers and an ink supply port formed by anisotropicetching of a silicon single-crystal substrate; a nozzle plate havingnozzle openings at the same pitches as those of said pressurizingchambers, said nozzle plate being attached to one face of said spacer;and an elastic plate for selectively expanding and contracting saidpressurizing chambers, said elastic plate being attached to another faceof said spacer, wherein each of said pressurizing chambers is formed asa recess by half etching of said silicon single-crystal substrate, and anozzle communicating hole is formed as a through hole by laserprocessing.
 19. A method of producing an ink jet recording head,comprising the steps of: (a) forming a recess on one face of a siliconsingle-crystal substrate by anisotropic etching; (b) forming a throughhole in a region of said recess by laser processing; and (c) fixing anelastic plate to a face on the side of an opening of said recess, and anozzle plate to another face.
 20. A method of producing an ink jetrecording head, comprising the steps of: (a) forming a through hole at aposition opposing a nozzle opening of a silicon single-crystalsubstrate, by laser processing; (b) forming a recess on one face of saidsilicon single-crystal substrate by anisotropic etching; and (c) fixingan elastic plate to a face on the side of an opening of said recess, anda nozzle plate to another face.
 21. An ink jet recording headcomprising: a passage unit comprising, a spacer/forming a pressurizingchamber and a common ink chamber, and an elastic plate abutting againstan end of a piezoelectric vibrating element; and a fixing substrate forfixing said piezoelectric vibrating elements thereto at regular pitchesa frame for fixing said passage unit at a surface and said fixingsubstrate, said frame comprising, an opening at one end, a windowthrough which the end of said piezoelectric vibrating element isexposed, at another end, an overhang portion which overhangs to avicinity of said elastic plate, and a groove for injecting an adhesiveformed on a wall face extending from a vicinity of said opening to saidoverhang portion, wherein said fixing substrate and said frame are fixedto each other by an adhesive.
 22. An ink jet recording head according toclaim 21, further comprising a wedge-like gap upwardly expanding andopening formed between said fixing substrate and said frame, whereinsaid fixing substrate and said frame are fixed to each other by anadhesive injected into said gap.
 23. An ink jet recording head accordingto claim 21, further comprising a gap formed between said overhangportion and an end of said fixing substrate, wherein said fixingsubstrate and said frame are fixed to each other by an adhesive injectedinto said gap.
 24. An ink jet recording head according to claim 21,wherein a plurality of said grooves are formed so as to be symmetricalin the arrangement direction.
 25. An ink jet recording head according toclaim 21, wherein said groove elongates to said overhang portion.
 26. Anink jet recording head according to claim 21, wherein said grooveelongates to a vicinity of said overhang portion.
 27. An ink jetrecording head according to claim 21, wherein said groove is formed soas to upwardly expand and open.
 28. An ink jet recording head accordingto claim 21, wherein a recess which guides said fixing substrate has asurface in which said groove is formed.
 29. A method of producing an inkjet recording head, comprising the steps of: fixing a passage unit inwhich a nozzle plate having a nozzle opening, a spacer forming apressurizing chamber and a common ink chamber, and an elastic platehaving a thick portion abutting against an end of a piezoelectricvibrating element are stacked, to an opening of a frame having anoverhang portion which overhangs to a vicinity of said thick portion;inserting a vibrating element unit into said frame, said vibratingelement unit being configured by fixing a plurality of piezoelectricvibrating elements operating in a longitudinal vibration mode to afixing substrate; and injecting an adhesive into a groove formed in aregion opposing said fixing substrate of said frame.
 30. An ink jetrecording head comprising: a piezoelectric vibrating element unitcomprising, a plurality of piezoelectric vibrating elements, and afixing substrate fixing said piezoelectric vibrating elements thereto atregular pitches; a passage unit comprising, a spacer forming apressurizing chamber and a common ink chamber, and an elastic platehaving a thick portion abutting against an end of each of saidpiezoelectric vibrating element; a frame to which said passage unit andsaid piezoelectric vibrating element unit are fixed while abutting saidpiezoelectric vibrating element against said thick portion; and a buffermember interposed between said frame and said passage unit, said buffermember being made of a material having a linear expansion coefficientbetween that of a linear expansion coefficient of said frame and alinear expansion coefficient of said passage unit.
 31. An ink jetrecording head according to claim 30, wherein said piezoelectricvibrating element unit comprises a dummy piezoelectric vibrating elementat both ends, and said buffer member comprises a window for guiding andpositioning said dummy piezoelectric vibrating elements.
 32. An ink jetrecording head according to claim 30, wherein said buffer membercomprises an overhang portion which protrudes over said frame towardsaid piezoelectric vibrating element.
 33. An ink jet recording headaccording to claim 30, wherein a slope in a thickness direction isformed in an end region of said fixing substrate.
 34. An ink jetrecording head according to claim 30, wherein said buffer member is madeof a metal or a resin.
 35. An ink jet recording head according to claim30, wherein a thin portion is formed in a region of said elastic plateopposing said common ink chamber, and a recess is formed in a region ofsaid buffer member opposing said thin portion of said elastic plate. 36.An ink jet recording head according to claim 31, wherein an end of thefixing substrate does not protrude from the overhang portion.